Reversely bent resilient retainer for digging implement blades



Oct. 10, 1967 cs. A. PETERSEN.

REVERSELY BENT RESILIENT RETAINER FOR DIGGING IMPLEMENT BLADES Filed May 5, 1965 2 Sheets-Sheet 1 INVENTOR- GERALD A. PETERSEN who A T TO/PNEV Oct. 10, 1967 G. A. PETERSEN REVERSELY BENT RESILIENT RETAINER FOR DIGGING IMPLEMENT BLADES Filed May 5, 1965 s-Sheet 2 AfTOQ/VEV United States Patent 3,345,765 REVERSELY BENT RESILIENT RETAINER FOR DIGGING IMPLEMENT BLADES Gerald A. Petersen, Sunnyvale, Calif., assignor of one-half to Anita E. Petersen, Saratoga, Calif. Filed May 5, 1965, Ser. No. 453,422. 8 Claims. (Cl. 37-142) This invention relates to a new and improved reversely bent resilient retainer for digging implement blades. The resilient retainer is positioned between the blade and its holder and provides resistance to unintentional disengagement of the parts. This application is a continuationin-part of copending application, Ser. No. 418,073, filed Dec. 14, 1964, for Resilient Retaining Means for Digging Implement Blades.

The present invention has particular application to the removable blades of earth digging machines, such as graders, clippers, back hoes, harrows, scarifiers, cable plows, and similar equipment wherein the blade is subjected to heavier stresses and generally is larger than the removable teeth to which the resilient retainer principle .has heretofore been applied. In heavy equipment of the type to which this invention is most applicable, a tooth formed with a hollow or recess is driven into or over a shank attached to a permanent part of the machine. The blade frictionally engages the shank, or is welded thereto, or various keys are used to hold the parts in place, or one of the mating parts is deformed as by swedging, dimpling, staking, or the like. The forces applied to the blade in use tend either to drive the blade so firmly into engagement with the shank as to make it difficult, if not impossible, to separate when replacement of the blade is required, or, on the other hand, tend to separate the two parts by reason of the extreme and unpredictable stresses to which the blade is subjected. In accordance with the present invention, a resilient retainer is positioned between the blade and the shank, with an extended area of surface contact between the insert and the two parts which it engages, so as to frictionally hold the blade on its shank against unintentional dislodgment despite extreme stressestending to separate the parts. On the other hand, since the resiliency of the insert is an important feature of the invention, the forces tending to prevent dislodgement of the two members when it is necessary to replace the blade are largely overcome and it is merely necessary to apply suficient force in the proper direction to overcome the frictional resistance.

Accordingly, it is a principal purpose of the present invention to provide means for retaining a blade on a permanent portion of a machine in such manner that it may be removed and sharpened, replaced, or otherwise repaired, and yet to provide a secure enough retention to prevent unintentional separation.

A particular advantage of the present invention is the facility with which the blade may be installed and removed and the fact that no special tools or other equipment are required for such purpose.

Still another advantage of the invention is the fact that the resilient insert which secures the blade on its holder accommodates minor variations in the construction of the blade and holder'and thereby makes close tolerances of dimensions of the mating parts unnecessary, and further accommodates wear of parts with passage of time.

As hereinafter described in detail, the resilient retainer is inserted in holes in the tooth holder and the ends of the retainer extend into the recess in the holder and are positioned between the blade and the holder when the blade is forced into the holder. Grooves may be formed in the holder and the internal ends of the resilient re- Patented Oct. 10, 1967 "ice tainer are compressed between the bottoms of the grooves and the adjacent wall of the blade. The cross-sectional shape of each groove is preferably substantially different from the initial unstressed shape of the resilient insert and hence there is a considerable deformation of the insert which increases the area of surface contact between the insert and the holder and the blade. Hence, the resistance to unintentional dislodgment of the blade from the holder is increased. When there is sufficient clearance between blade and holder, use of grooves may be eliminated.

Another principal feature of the present invention is the fact that neither bolts, metal keys, nor similar fasteners, nor welding to secure the blade on the shank are used, thereby eliminating a considerable amount of the difficulty heretofore occasioned in securing blades to their holders and removing the blades from the holders when required.

A distinguishing feature of one form of the invention hereinafter described is the doubling over of the resilient retainer so that there are two ends, both of which are compressed so as to retard separation of the parts, thereby materially increasing the resistance to withdrawal of the blades from the recess in the holder. A single retainer is bent in a U-shape and both of the ends are inserted through holes in the toothholder wall, the metal between the holes serving to prevent the retainer from being pulled into the holder. The exterior wall of the holder may be recessed so that the bent over portion of the retainer is protected against abrasion by being located below the exposed surface of the holder.

In one form of the invention hereinafter described, the holder and tooth are so constructed that the tooth may be reversed. In other words, the tooth is provided with two working ends which can be used alternately, the tooth and the recess in the holder being so shaped as to accommodate either of the working ends of the tooth. This alternate construction increases the overall life of the tooth and the means of holding the tooth in its holder is such as to facilitate removal for reversal of the tooth.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

FIGURE 1 is a side elevational view partialy broken away to censerve space of a tooth and holder in accordance with the invention.

FIG. 2 is an enlarged fragmentary mid-sectional view through FIG. 1.

FIG. 3 is a transverse view in enlarged scale, taken substantially along the line 33 of FIG. 2.

FIG. 4 is an enlarged fragmentary bottom plan view taken substantially along the line 44 of FIG. 1.

FIG. 5 is a transverse sectional view in enlarged scale taken substantially along line 55 of FIG. 3.

FIG. 6 is a fragmentary view similar to FIG. 5 of a modification.

FIG. 7 is a perspecive view of a tooth according to FIG. 1.

FIG. 8 is an end view of the tooth of FIG. 7.

FIG. 9 is a view similar to FIG. 7 of a further modification.

FIG. 10 is a view similar to FIG. 2 showing use of a tooth according to FIG. 9.

In the form of the invention shown in FIG. 1,.blade 11 of a typical suitable on heavy equipment of the type of road graders, rippers, dipper buckets, and other machines where blades of comparatively large size and heavy weight are used and are subjected to severe stresses in unpredictable directions. A shank or a holder 12 is secured by means forming no part of this invention to a permanent part of the equipment and the blade 11 is held relative to shank 12 at an angle best suited for the performance of its function, such as that shown in FIG. 1. The lower end 13 of holder 12 is bent generally parallel to the working portion of blade 11 and then extends upwardly in a stretch 14 at an angle to portion 13. The corner 16 at the bottom of portion 14 is preferably curved to reduce resistance to the performance of the function of blade 11.

The shape of blade 11 is subject to considerable variation. In the form of the invention shown in FIG. 1, the distal portion is formed with top surface 17 having a longitudinal medial crest 18 and downward-outward sloping faces to either side of said crest 18. The bottom surface 19 has a similar longitudinal medial crest 21, and upward-outward faces to either side of said crest 21. The side edges 22 of the distal portion are substantially vertical. Bottom surface 19 tapers upwardly to a broad, blunt transverse forward end 23. The prdximal end of blade 11 has a downward protruding extension 26 which is T-shaped in cross-section, extending longitudinally of the tooth. Forward of extension 26 is a forward converging gusset 27 on the bottom side of the tooth which terminates spaced rearwardly of end 23. Directing attention particularly to FIG. 3, extension 26 depends from the underside of blade 11, said underside having upwardlyoutwardly extending faces 28 to either side of a downward leg 29 which has substantially vertical side edges 31. The lower end of leg 29 is provided with outward extending feet 32. The upper surfaces 33 of feet 32 are outwarddownward sloping, the side edges 34 are substantially vertical and the bottom surfaces 36 are upward-outward extending. Extension26 terminates in a substantial straight end 37 (see FIG. 2).

Tooth 11 is preferably wider than holder 12 and also extends further forward and lower in digging position so that the hard tooth protects the holder from abrasion while the tougher holder absorbs the shock of obstructions to digging action. The forward upper portion of extension 13 of holder 12 is formed with a recess extending back from its forward end which is complementary to extension 26 and terminates in a rearward shoulder 38 against which end 37 abuts. The top of forward end 13 has upward-outward slanted surfaces 41, which are parallel to and in close proximity to surfaces 28 of blade 11. A downward slot is formed extending medially longitudinal having substantially vertical opposed edges 42 in proximity to and spaced substantially the same distance apart as edges 31. Below edges 42 the recess widens out and has downward-outward slanted faces 43 parallel and in proximity to surfaces 33. The sides 44 of the recess are parallel and in close proximity to edges 34 of extension 26. Bottom surface 46 is spaced below surfaces 36. The fit between the mating parts is such that the blade and holder could readily be withdrawn relative to each other if no locking means are employed. A resilient insert 47 is employed to hold the parts together. Insert 47 is formed of a resilient material, preferably an elastomeric material such as neoprene synthetic rubber. However, natural rubber, other synthetic rubber, nylon cord, latex-dipped nylon cord, soft-iron wire, or other resilient substances may be used. The cross-sectional shape of insert 47 in its initial dimension is circular. In the form of the invention here shown, a distinguishing feature of the use of insert 47 is that it is initially bent in a substantially U-shaped form so as to provide two ends which fit into the recess in holder 12. To provide entry for inert 47, an opening 48 is formed in the bottom surface 49 of lower portion 13. The depth of opening 48 is such that insert 47 is substantially concealed therewithin so that abrasion during the digging action of the blade does not tend to damage any exposed portion of insert 47. A pair of holes 51 ex tends upward-rearward from opening 48 through bottom surface 46 of the recess heretofore described. The inner ends 52 of insert 47 are of extended length and are compressed between surfaces 46 and 36 and are distorted to the shape shown in FIGS. 2 and 4. The distortion of the cross-sectional shape of insert 47 augments the area of surface contact of the deformed portions 52 with surfaces 46 and 36 and thus increases resistance to withdrawal of the tooth from its holder. The length of the distorted portions 52 is sufficient to accommodate the reduction in cross-section. Since the blade 11 is held in its holder by a resilient insert 47, it is not necessary to make the clearance between the parts so tight that the force of digging action jams the blade into its holder so that it cannot subsequently be withdrawn. All that is necessary to separate the two parts is to drive the end 37 of the blade in a longitudinal direction from the rear with a hammer or other tool until the frictional resistance of the separation is overcome.

It will thus be seen that the first step in insertion of tooth 11 in holder 12 is to bend insert 47 in a U-shape and to insert the ends 52 into the recess 48 in the holder until the insert is concealed therewithin. Thereupon tooth 11 is inserted in the recess in the holder and driven rearwardl-y until end 37 seats against shoulder 38 with ends 52 compressed between surfaces 36 and 46. Insert 47 frictionally resists withdrawal of the tooth from its holder despite considerable forces from various angles operating on the tooth.

FIG. 6 shows a modification wherein grooves 53 are recessed into surface 46a and the clearance between surfaces 36a and 46a is reduced. Corresponding elements are designated by the same reference numerals followed by subscript a. Grooves 53 are preferably wider and shallower than the corresponding uncompressed shape of insert 47.

Referring to FIG. 2, it will be seen that as an optional feature of construction slot 56 complementary to gusset 27 may be formed in the rearward end of the recess above shoulder 38, and that the forward end 57 of extension 26 is parallel to end 37. Although in the form of the invention shown in FIGS. 1 to 4, inclusive, the proximal top surfaces 58 of the tooth taper rearw-ardly-downwardly, nevertheless in the form of the invention shown in FIGS. 9 and 10, surfaces 58b are straight and parallel and a second distal portion 1711 similar in shape to portion 17 is formed in the rearward end of the tooth, corresponding elements which are similar to elements in the forward end being designated by the same reference numerals followed by the subscript b. The gusset 27 fits into the slot 56. In this form of the invention, therefore, there are two ends 23 and 23b to perform cutting action which may be used alternately. When one end 23 is worn, the tooth may be removed from its holder and reversed and the opposite end 2311 used. The shape of extension 26 of the recess in which it fits facilitates this reversal.

Although the foregoing invention has been described in some detail, by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. In earth digging equipment, a blade holder member formed with a recess having at least one first wall, a blade, said blade having a distal portion shaped with a cutting edge and a proximal portion, said proximal portion having at least one part thereof shaped complementary to said recess, said part having a second wall facing and in proximity to said first wall with a space between said Walls, said holder having a pair of openings communicating with said space, and a resilient insert doubled over and having a pair of ends extending through said openings and into said space and positioned between said walls to frictionally restrain relative movement of said blade and said blade holder, said recess and said extension being T-shaped in cross-section, said extension having a leg and transverse feet, said walls extending across said feet, said part of said proximal portion being a projection from said blade spaced downward and rearward from said distal portion and having a blunt rearward end, said recess having a rear wall against which said end of said part abuts to limit inward movement of said blade.

2. The combination of claim 1, in which said blade is formed with a second distal portion opposite said firstmentioned distal portion and shaped with a second cutting edge, said part of said proximal portion fitting into said recess in opposite directions to mount said blade in said holder with either of said cutting edges in working position.

3. The combination of claim 1, in which said blade is reversible end-to-end and said part of said proximal portion is reversably insertable in said recess.

4. In earth digging equipment a blade holder having a forward opening recess shaped as an inverted T in crosssection and having a bottom wall formed with a pair of apertures extending from the exterior of said holder into said recess, said recess having a rear shoulder, a blade having at least one cutting end and a downward protruding extension remote from said end and having a rearward abutment abutting said shoulder, said extension substantially complementary to said recess, and a resilient insert bent over exteriorly of said holder and having its ends extending through said apertures into said recess and compressed between said extension and said holder to restrain withdrawal of said extension from said recess.

5. The combination of claim 4, in which said blade is formed with a second cutting end opposite said first-mentioned cutting end, said extension is reversible end-to-end in said recess to expose either of said cutting ends in working position.

6. The combination of claim 5, in which said holder is formed with a depression adjacent said apertures, the bent-over part of said insert being received in said depression.

7. A holder for an earth digging blade having a forward opening recess shaped as an inverted T in crosssection and having a top wall formed with a longitudinal narrow slot, closed side walls and a bottom wall formed with a pair of apertures extending from the exterior of said holder into said recess, said recess having a rear shoulder, and a resilient insert doubled over and having a pair of ends extending through said apertures and into said recess.

8. A holder according to claim 7, in which the exterior of said holder is formed with a depression between said apertures, said depression of a depth at least as great as the widthof said apertures, the doubled over part of said insert received in said depression.

References Cited UNITED STATES PATENTS 775,770 11/1904 Herrod 172-751 X 1,168,469 1/ 1916 Benson. 2,222,071 11/ 1940 Gust-afson 37-142 X FOREIGN PATENTS 103,025 1/ 1917 Great Britain.

ABRAHAM G. STONE, Primary Examiner.

A. E. KOPECKI, Assistant Examiner. 

4. IN EARTH DIGGING EQUIPMENT A BLADE HOLDER HAVING A FORWARD OPENING RECESS SHAPED AS AN INVERTED T IN CROSSSECTION AND HAVING A BOTTOM WALL FORMED WITH A PAIR OF APERTURES EXTENDING FROM THE EXTERIOR OF SAID HOLDER INTO SAID RECESS, SAID RECESS HAVING A REAR SHOULDER, A BLADE HAVING AT LEAST ONE CUTTING END AND A DOWNWARD PROTRUDING EXTENSION REMOTE FROM SAID END AND HAVING A REARWARD ABUTMENT ABUTTING SAID SHOULDER, SAID EXTENSION SUBSTANTIALY COMPLEMENTARY TO SAID RECESS, AND A RESILIENT INSERT BENT OVER EXTERIORLY OF SAID HOLDER AND HAVING ITS ENDS EXTENDING THROUGH SAID APERTURES INTO SAID RECESS AND COMPRESSED BETWEEN SAID EXTENSION AND SAID HOLDER TO RESTRAIN WITHDRAWAL OF SAID EXTENSION FROM SAID RECESS. 